Production of colored glasses



United States Patent Oiiice A 3,003,886 Patented Oct. 10, 1961 This invention relates to colored glass and more particularly to a novel method and glass batch constituents for producing either opal or transparent colored glasses. More specifically the invention rel-ates to the production of stable colored glasses, namely, opaque opal glasses varying in color from light ivory to dark brown and transparent soda-lime or soda-potash-lime glasses varying in color from yellow to dark amber, all of which are adaptable to melting and lining in continuous tank furnace operation.

The term opal glass or opalescent glass, as used herein, denotes any glass which has a light diffusing medium or phase therein which renders the glass essentially light difiusing and thus translucent or opaque. Opol glasses of various types are well known in the glass making art and some of the opalizing agents utilized heretofore have been fluorides, sulphates, chlorides and phosphates. Fluoride opal glasses have been known to be particularly desirable for illuminating purposes in having Wide latitude of opal density. -Other common forms of opal glasses have consisted of fire .opals and alabaster glasses for producing illuminating glassware as well as various forms of art were.

Previously in the production ofivory colored opaque opal glasses such as for structural panels, bottles or jars, difficulty has been experienced in compounding glass batch constituents having ivory colors satisfactory to the trade. This has been particularly true in producing such opalescent glasses as special ivory or light yellow colorations and many attempts have been made to produce such glasses by combinations of uranium and selenium oxides which materials are very closely and not readily available for this purpose. Also in producing colored opaque glass for architectural structures, problems have arisen in the fading or change in color of such glasses on prolonged exposure to sunlight. This has been true where the colorants have consisted of uranium and manganese oxides, for example.

Heretofore, selenium ruby glasses suitable for tank furnace melting, and especially for the production of machine-made ware, have been prepared from glass batch constituents using reducing agents such as carbonaceous materials or silicon and selenium in combination with a coloring-agent such as selenium sulphide. The production of such selenium ruby glasses has been disclosed in US. Patent No. 2,414,413, issued to Pavlish and Austin on January 14, 1947, and entitled Selenium-Containing Glass. It is disclosed therein that the loss of selenium from glass batches during melting and fining operations can be minimized by the addition to the batch of siliconcontaining materials. Silicon is utilized therein as a reducing agent to'retain specifically the selenium added to the batch at an optimum level in producing selenium ruby glass. This patent describes that small additions either of metallic silicon or chemically combined silicon make possible the reduction of the selenium addition to about /3 or less of that normally required in the glass batch. it should be noted that this patent relates only to making selenium containing glasses and specifically selenium ruby. There is no teaching in the prior art of producing and controlling the coloration of light-diffusing ivorycolored opal glasses, for example, or transparent sodalime glasses through a wide range of colors by the addition of small amounts of very economical materials such as described hereinafter.

Accordingly, it is an object of this invention to provide a novel method of coloring glass by utilizing in combing tion within a glass batch minor amounts of a readily reducible chemically combined material adapted to impart coloration to the glass and a readily oxidi zable glass-1 forming elemental which alone does'not impart coloration to the glass.

Another object of the invention is to provide an improved method of producing colored glasses ranging in color from light ivory to dark brown for opaque opal glasses and from light yellow to dark amber for transparent soda-lime or soda-p'otash-lime glassesby the use of readily available economical components employed in small amounts which do not deleteriously aifect the characteristics of the colored glass'product. j

Another object of this invention is to provide an improved method of and glass batch for producing an opaque opal glass varying in color from light ivory to dark brown by incorporating into a fluoride opal glass batch a combined sulphur containing material and a glassforming elemental metal such as silicon or aluminum in powder form which alone does not impart a coloration to the glass nor adversely alter its characteristics if employed in slight excess.

A further object of this invention is to provide an improved method of and glass batch for producing acolored transparent soda-lime glass varying in coloration from light yellow to dark amber, which glass has good chemical durability and pleasing coloration and has suitable working properties for melting, fining and forming in a conventional manner.

The specific nature of the invention, as well as other objects and advantages thereof, will become apparent'to those skilled in the art from the following detailed description.

The present invention consists of producing a very economical chemically stable and durable opaque ivory colored opal or pale transparent amber glassand variations thereof by employing in combination with the glass batch constituents chemically combined sulphurand a glass forming elemental metal as a reducing agent, which metal does not alone produce color or perceptibly change the properties of the glass. In accordance with the invention only small amounts of the prescribed components are necessary to effect the coloration and this may be achieved without deleterious alteration of properties of a given glass. The readily reducible color producing con: stituent included in the glass batch comprises combined sulphur, preferably in the form of salt cake, pyrites, or gypsum, or other commercially available sulphur-containing glassforming material. For purposes of economyin the production of large amounts of the subject colored glasses, one of the aforementioned materials is preferably employed. The glass forming elemental metal which is employed as a reducing agent preferably consists of metal any coloring effects upon a melted glass.

tal metals such as calcium, magnesium, sodium, potassium, lithium, and barium can also be utilized as the re ducing agent instead of silicon or aluminum metal but for ease of handling the latter two are preferred. Zipc metal can also be used for this purpose. Various 'for'm's'ofsilicon can be used,however, metallugical gradejsilicon in powder form is advantageous due to its ease of handling, low cost and ready availability. 'BOWQQlgd aluminum metal is also readily available and economical.

It has been found that only small percentages of the elemental metal and combined sulphur are, required to produce the desired coloring effect. In Table I raw batch constituents and calculated batch compositions'are listed for five different opal glasses along with C.I.E. colorimetric data obtained thereon.

Table l OPAL GLASSES Batch Constituents 1 2 3 4 5 Powdered Flint 2,300 2,300 2, 300 2,300 2,153 584 354 534 554 555 1, 303 1,303 1,303 1,303 1,307 4 401 401 401 441 145 145 145 145 154 55 55 55 55 51 20 20 20 Salt Cake 1.1555 1.1555 1.1555 1.1555 14 Silicon (Powdered metal) 0. 3766 0.7532 7. 5 Aluminum (Powdered metal). 0.4826 Iron Pyrif 5. 8

Calculated Batch Composition:

s10, "percent" 55.22 55.21 55. 22 55. 20 55. 25 B101... do. 050 0.50 0.30 0.30 0.70 do-. 5. 74 5.74 5.74 5.74 5.70 14. 79 14. 79 14. 50 14. 51 12. 77 1. 33 1. 33 1. 33 1. 33 1. 33 5.14 5.14 5.14 5.14 7.24 0. 03 0. 03 0. 03 0. 03 0. 03 5. 71 5. 71 5. 71 5. 71 5. 75 -2. 40 -2. 40 -2. 40 -2. 40 -2. 55 0.50 0. 50 0. 00 0.50 0. 57

O.I.E.)Data $5 in. thick specii er'eent Brightness 58.4 57.2 73.0 75.4 10.2 Percent Purity 4. 5 12. 0 4. 9 0.8 36. 0 Dominant Wave Length 565 574 483 512 578 The Oxygen equivalent for fl t tio of 16/38, Glass designated as compositions Nos. 6-8 are transis subtracted from the total fluorine content to place the parent and each exhibits a distinctive coloration ranging analysis on a full oxide basis. from light yellow to dark amber. The constituents of In addition to the C.I.E. data mdicated above, comthese glasses may be modified considerably within preposition No. 1 may be described as a light ivory-colored scribed limits for conventional soda-lime glasses to pro opal while composition No. 2 may be described as a duce commercial glasses having desired working properslightly deeper shade of wow. Compo ltlon N0. t0 ties including necessary viscosities and liquidus temperawhich no elemental metal was added, may be described tu fo fabricating l s as an elf-White 0r b she e010rati01 1 h8-V1I1g the 1 Composition No. 6 may be termed a dark amber comp e of an alabaster glass composltlon 9; 4 y parable to amber beer bottle glass. Composition No. 7 be described as a hght ivory color wh1le composition No. 40 is a light-yellow greenish amber while composition No. 5 containing a considerably greater amount of elemental 3 may b d -ib d as a di amben A1] of h silicon exhibited an olive-brown coloration. Various inabove arent glasses were colored by minor additelmedllate Shades between llght y ellve-bl'own tions of combined sulphur and silicon metal added to the coloretlee y be achlevedhy vananofls amounts of batch constituents. These glasses also contained a small the combined sulphur containing material and elemental amount f added i metal. In the deeper shades iron is added to the batch to I has been fou d that fl id Opal glasses may be enhance the 9 Wh 11e the llghtel shedes Iron 15 colored from opaque light ivory to opaque dark brown troduced as an l y 1n the raw materlalby incorporating into the glass batch from 0.065 to 2.55 In Table II set forth below, the raw batch constituents parts by weight sulphur per 1000 parts of silica, th 1. and calculated batch composltlons 0f tfansparellt phur being present in chemically combined form, with glasscompositlons are set forth along with C.I.E. colonan addition f elemental metal ranging in amount fr data defimng COIOIS- 0.086 to 3.91 parts by weight metal per 1000 parts of Table II silica. This range of metal has been found to be satis- TRANSPARENT SODA-LIME GLASSES factory for coloring with silicon metal, as indicated in the above tables, however in coloring with aluminum metal Batch cmsmuents 6 7 8 it has found that approximately twice as much metal is S d needed to develop the same colors. The amount of elefifi gggjj j 238 933 mental metal may be present in an amount of up to gigiscalcium Lime- 511 511 511 about 8 parts by weight metal per 1000 parts by weight G yDsiEI... i: i; of silica. The metal serves as the reducing agent to re- 1 0:; gyri g 5. 50 duce at least a portion of the sulphur to metallic sulfides s1i1mn5wi1er "1:; *1? 2. c s g s e gr p w e i e tion. e opa gass atc may consist o e o owing 35 1525 302fiff ii iifieneenn- 11.54 11.12 11. 57 constituents in calculated Percentage y Weight:

1. 55 1.55 1. s3 d 3:23 Ranges of opal glass constituents: A 15.42 1 1 11 S10 6075 1125 001121 0155 B203 .153 0.053 0. 052 A1 0 4-9 .242 0.245 0.230 Nazo 10-18 100.000 100.000 100.000 K 0 0-10 0.1.11. Data 14inch thickspecimen): CaO 011 Percent Brightness 52.0 77.7 53.0 Mg() 0-2 Percent Purity 74. 0 19. 7 51.1 Dominant Wave Length- 575 572 575 2 2 8 0-0.10 Sulphur 00043-0183 Elemental metal 00057-0280 Glass batches which have been found to be suitable for producing colored transparent soda-lime glasses ranging in color from yellow to dark amber have consisted of the following constituents in calculated precentage by weight:

Range of transparent soda-lime glass constituents:

Elemental metal 00057-0280 The present invention has been utilized commercially to a widespread degree in the production of glass con tainers and specifically in the production of ivory opal bottles and jars for retaining lotions and deodorants. The glasses can be readily melted and formed with conventional glass melting, fining and forming equipment with satisfactory uniform colors free from streaks and blemishes. Such conventional melting, fining and forming conditions are well known in the art and are particularly set forth in Tooleys Handbook of Glass Manufacture, Ogden Publishing Company, New York 36, New York, 1953 edition, at page 245 in Tables IXB-I and IXB-II, and as further explained in pages 242-252. The method has been employed in the production of the wellknown Old Spice lotion bottle sold and distributed by the Shul-ton Company to contain shaving lotions and deodorants to simulate pottery ware.

The C.I.E. colorimetric values are based upon the OLE. chromaticity diagram. C.I.E. refers to the International Commission of Illumination and the diagram defines color in terms of mixtures of theoretical 'clored lights. The C.'I.E. system makes possible the exact specification of colors by means of a color map. The C.I.E. system of color notation specifies the color of glasses in terms of brightness, purity and dominant wave length. Brightness, which is usually expressed in terms of percentage, is the amount of visual response to a normal observer to the radiation emergent from a transparent object relative to the response in this observer to the radiation incident upon the object. Thus, brightness may be briefly termed the lightness of color of an object. Purity, which is also normaly expressed in terms of percentage, is a measure of the monochromaticness of a color with monochromatic light having a purity of 100%. By diluting the monochromatic radiation with white light made up with all wave lengths, we thereby dilute the color and reduce purity. Dominant wave length, usually expressed in milli-micron's (mg), is the wave length of monochromatic light appearing to the eye to have the same hue as the mixed light actually encountered.

Various modifications may be resorted to within the spirit and scope of the appended claims.

I claim:

1. The method of producing colored opal glass ranging in coloration from opaque light ivory to opaque dark brown comprising the steps of providing an opal glass batch consisting essentially of the following constituents in calculated percentage by weight: -75% SiO 02% B 0 49% A1 0 10-18% Na O, 0-10% K 0, 0-11% CaO, 0-2% MgO, 4-8% F 02% ZnO, 0-0.10% Fe O 0.0043-0.183% sulphur, and 0.0057-0.280% glass-forming elemental metal in powder form selected from the group consisting of silicon, aluminum, zinc, barium, calcium, magnesium, sodium, potassium and lithium, said sulfur being included in said batch in readily reducible form, melting the said batch constituents, by heat-reaction in a melting chamber, effecting a reduction of at least a portion of said sulfur to metallic sulfides within said melting chamber to etfect coloration of the molten glass, said elemental metal becoming oxidized and producing no coloration, and conveying the said molten glass to a point of use.

'2. The method of producing colored opal glass ranging in coloration from opaque light ivory to opaque dark brown comprising the steps of providing an opal glass batch consisting essentially of the following constituents in calculated percentage by weight: 60-75% SiO 02% B 0 4-9% A1 0 10-18% Na O, 0-10% K 0, 0-11% CaO, 02% MgO, 4-8% F 0'-2% ZnO, 0-0.10% Fe O 0.0043-0.183% sulphur, and 0.0057-0.280% glass-forming elemental metal in powder form selected from the group consisting of silicon and aluminum, said sulfur being included in said batch in readily reducible form, melting the said batch constituents by heat-reaction in a melting chamber, effecting a reduction of at least a portion of said sulfur to metallic sulfides in situ within said melting chamber to effect uniform coloration of the molten glass, said elemental metal becoming oxidized and producing no coloration, and conveying the said molten glass to a point of use.

3. A glass batch for producing colored opal glass ranging in coloration from opaque light ivory to opaque dark brown consisting essentially of the following constituents in calculated percentage by weight: 60-75% SiO 02% B 0 4-9% A1 0 10-18% Na O, 0-10% K 0, 0-11% 0210, 0-2% MgO, 4-8% F 02% ZnO, 0-0.10% Fe O 0.00430.183% sulphur, and 0.0057-0.280% glass-forming elemental metal in powder form which metal alone does not impart coloration to the glass, said metal being selected from the group consis'tmg of silicon, aluminum, zinc, barium, calcium, magnesium, sodium, potassium, and lithium.

4. A glass batch in accordance with claim 3, wherein said elemental metal comprises silicon.

5. A glass batch in accordance with claim 3, wherein said elemental metal comprises aluminum.

References Cited in the file of this patent UNITED STATES PATENTS 1,864,858 Rising 2 June 228, 1932 1,899,230 Crowell Feb. 28, 1933 2,113,195 Flint Apr. 5, 1938 2,282,601 Blau et al May 12, 1942 2,414,413 Pavlish et al. Jan. 14, 1947 2,503,140 Stookey Apr. 4, 1950 2,921,860 Stookey Jan. 19, 1960 

2. THE METHOD OF PRODUCING COLORED OPAL GLASS RANGING IN COLORATION FROM OPAQUE LIGHT IVORY TO OPAQUE DARK BROWN COMPRISING THE STEPS OF PROVIDING AN OPAL GLASS BATCH CONSISTING ESSENTIALLY OF THE FOLLOWING CONSTITUENTS IN CALCULATED PERCENTAGE BY WEIGHT: 60-75% SIO2, 0-2% B2O3, 4-9% AL2O3, 10-18% NA2O, 0-10% K2O, 0-11% CAO, 0-2% MGO, 4-8% F2, 0-2% ZNO, 0-0.10% FE2O3, 0.0043-0.183% SULPHUR, AND 0.0057-0.280% GLASS-FORMING ELEMENTAL METAL IN POWER FROM SELECTED FROM THE GROUP CONSISTING OF SILICON AND ALUMINUM, SAID SULFUR BEING INCLUDED IN SAID BATCH IN READILY REDUCIBLE FORM, MELTING THE SAID BATCH CONSTITUENTS BY HEAT-REACTION IN A MELTING CHAMBER, EFFECTING A REDUCTION OF AT LEAST A PORTION OF SAID SULFUR TO METALLIC SULFIDES "IN SITU" WITHIN SAID MELTING CHAMBER TO EFFECT UNIFORM COLORATION OF THE MOLTEN GLASS, SAID ELEMENTAL METAL BECOMING OXIDIZED AND PRODUCING NO COLORATION, AND CONVEYING THE SAID MOLTEN GLASS TO A POINT OF USE. 